Method of producing a chain link and the link made by such a method



Dec. 12, 1933. G. H. GREEN 1,939,346

METHOD OF PRODUCING A CHAIN LINK AND THE LINK MADE BY SUCH A METHOD Original Filed Oct. 2. 1929 Inventor Gear gelf Green,

Patented Dec. 12, 1933 mrnonor monoomo A" chain LINK mm BYSUCHAMETHOD George Henry Green, Knkllton Fields, Leicester, England, assign! to The Economic Winding! Company Limited, Leicester, England Original application October 2, 1929, Serial No.

' 396,796, and in Great Britain September 14,

V 192. Divided and this application November 10, 1931. Serial No. 574,164

' 7 Claims.

This invention comprises an improved method of producing a chain link and the invention covered by this case is a division of an application filed by the applicant on 2nd October, 1929, un-

der Serial No; 396,796. V

The present invention has reference to a method of producing individual links of an articulated sprocket chain of the type described in the specification accompanying my concurrent ap- 1o plication for patent numbered as above and to the links made by such method.

Thepresent invention relates to manufacture of an articulated chain wholly or partly composed of duplicate links which are connected together in a readily removable manner and have a pivotal interlocking engagement one with another. Each of the said links is formed from a unitary portion of metal rod or wire and essentially comprises a rear bar portion, two side bar portions and front portions formed integral with the said side bars and constituting a composite connecting hook by means of which the link is adapted to be engaged with the rear bar of an adjacent link in the chain.

The object of the present invention is to provide an economical and efiective method of producing a chain as above, and consists in bending a unitary portion of metal rod or wire into a U-shape, bending the end portions of the arms of the U out of the plane of the saidU, bending the said arms towards each other at positions near the last-formed bends to cause the said end portions to be positioned side by side closely ad'- jacent to each other, and bending the said end 3 portions to form a composite hook.

In order that the invention may be more clear- .ly understood reference will now be made to the accompanying drawing, whereinz- Figure 1 illustrates in perspective three con- 7 nected links of an articulated sprocket chain produced in accordance with the present Figure 2 is an enlarged perspective view of a single link of the said chain, and

Figm'e 3 illustrates in perspective diflerent mm which the 1m: shown'in Figure} takes limited in application to such machines and may 1 be used on agricultural and other machines.

The chain is composed of links a each formed from a single length of wire bent and shaped to form a substantially rectangular main portion a' and an integral hooked connecting portion a composed of the two extremities of the length of wire suitably bent and shaped as hereinafter described the hook being of a width closely approximating the width of the sprocket opening in the links, between the side bars thereof. 7

The hook a of the link is adapted to be slid laterally over the rear bar a of the rectangular portion of the next link to connect the chain links together, suitable laterally extending notches a being provided in the side bars of each link. The hook a of each link extends around more than half of the circumference of the rear link bar a with which it engages, and the before-mentioned lateral notches a are stamped in the side bars of the link to enable the said hook to he slid laterally over the said side bars and pivotally engage with the rear :bar a of the link. V

In accordance with the present invention a chain link as above is formed from a single length of metal wire, preferably, steel wire of circular section, by a cold bending and pressing process, i. e., by bending and pressing the unitary portion of wire to the shape of the finished link without necessitating heating-and softening of the wire. 7

The chain link herein described and illustrated has a rectangular eye or opening to receive the tooth of a. sprocket wheel, such shape being necessary that there may be the front cross bar,- the bar carrying the coupling hook which is integral therewith-against which the sprocket tooth bears when in operation.

The production of the link may be carried out onany suitable known type of metal pressing machine and the method of production includes the following operations:

Operation 1 0L and two side arms a extending at right angles from said bar.

operatiortz For this operation the U-shaped length of Q rod is removed from the aforementioned die and is positioned horizontally in a U-shaped recess in another stationary die which vhas one .or two V-shaped projections at one or both sides of the said die near that part of the recess adapted to receive the rear bar a of the said: rod, and a stamping die having a'simil'ar recess and one or more similar projectionsdescends to stamp the notches a in the rod.

Operation 3 Y Consists in horizontally positioning the U-.-'

' arm portions (1 disp osedhorizontally andlthe remaining arm portions (1 extending downwardly therefrom, and descending and inwardly'closing press tools engage the arm portions a and "a' just below the bends made in operation 3, press the said portions a? together, and close the link, a double crank bend being formed at the front shoulders of the link as shown. Simultaneously in this operation. the end portions m are flattened by the descending tools.

Operation 5 I V In this operation the partly formed link is held at. the rear of a round-ended hardened steel projection around which the projecting end portions a of the link are bent partly to form the composite hook portion a Operation 6 i The link is finished in this operation by fur-' ther pressing the end portions a around a pin or spindle member 11 positioned in the press, which pin member is of the same diameter as the rear bar a of thelinkQ This operation bends the ends of the hook portiona so that they'extend around more than half the" circumference of the pin member at and will, therefore, extend around more than half the circumference of the rear bar of an adjacent link in the chain and prevent the said links from being disengaged otherwise than by being slid laterally relatively to each other. 'The operation also definitely locates the curved inner surfaces a of the hook correctly in relation to the other parts of the link and assures accurate alignment of the chain when the individual links are connected. It is also preferable during this, final, operation further to compress the metal of'the'endpor- ,tions (1 which'constitute the hook a and thereby increasethe tensile strength. of the said hook.

: I In order to prevent an undue, amount of relative lateral movement between the connected links for the chains for use in agricultural maoperation 4, or in the final operation, so that the width across the composite hook is just less than the distance between the two side bars of the link. "In large sizes of links, particularly so chinery, it is necessary to use rod of comparatively large diameter to obtain this desired width across the hook, and in order that the hook should'not'be cumbersome and out of proportion to the other parts of the link, the diameter of the rear bar a may be reduced by compressing the metal thereof and this may conveniently be efiected during operations 1 and 2. For example, in operation 1 the downward pressure of the press tool may compress the rear bar to an adapted to accommodate the said bar can then be, of normal proportion.

If desired, the two bent portions of the composite hook a may be electrically or otherwise welded together at a subsequent, operation in orderfurther to strengthen the'said hook.

It may also be desired to provide projecting cam or high link portions a (see Figure l)' on certain of the links and such portions may be electrically welded, thereon, preferably after the completion 'of the manufacture of the links, the said portions a being suitably'formed and shaped separate vfrom the link.

The type of chain which is made according to the method that has been described-sprocket chainis one that must possess strength,'have accuracy of shape, and be capable. of withstanding great tension and indefinite repetition of ar- I ticulation, without weakening or deformation. The method described insures the production of such a chain in a relatively simple manner. It will be noted that the shaping of the individual links is accomplished by purely .bending opera- 7 tio'n'supon the metal rod' from which the link is formed, without any twisting or torsionalaction thereupon, which twisting is very undesirable, as

is apparent.

I claim:- U 1. The method of 'producinga chain link of the type set forth, having a rectangulareye to receive a sprocket tooth and an integraljhook of a. width closely approximating the width of the eye for the sprocket tooth which consists in bending a unitary portion of metal rod or wire into a U-shape, bending the end portions of the arms of the U out'of the plane of the said U, bending the said arms at right angles and towards each other at positions near the last formed bends to cause the said end portions to bepositioned side by sideclosely adjacent 'to' each other, and

bending'the said end'portions to form a composite hook. I

2. Themethod of producing a chain link such -as:described in claim 1, including as an additional step flattening the portions of the link: that lie side by side preliminary to the formation of the composite hook.

3. The method of producinga chain link of the type set forth, having a rectangular eye and an integral hookoi a widthclosely approximating the width ofv the said eye which consists in bending a unitary portion of metal rod orwire into a U shape, bending the end portions of the arms of the U out of the plane of the said 'U to extend at right angles to the remaining portions of said arms, bending the said arm portions at right angles and at positions between the first and last-formed bends to cause the said end portions to lie alongside each other, and bending the said end portions to form a composite hook.

4. As an additional operation in the method described in claim 3, compacting the curved projecting end portions of rod about a supporting and shaping member finally to shape and strengthen the hook.

5. The herein described method of forming a link for a detachably connected sprocket chain, having a rectangular eye and a forwardly projecting hook of a width closely approximating the width of the saidrectangular eye, the hook being formed from the same piece of material as the other parts of the link which consists in taking a unitary portion of metal rod or wire, bending the said rod or wire into a U-shape having parallel arms of approximately equal length,

the several parts of the U thus formed being in a single plane, bending the end portions of the said arms out of the plane of the U and at approximately right angles to the remaining portions of the arms, bending the said arms at right angles at positions adjacent to the last formed bends and towards each other to close the link and form a double crank bend at each side and at the forward part thereof, and curving the projecting end portions about a supporting and shapmore than half 'of the circumference of a rear connecting bar of another link, including the stamping of notches at the rear extremity of the side bars of the link to enable the hook to he slid laterally thereover.

6. The method of forming, from metal rod or wire, a link for a sprocket chain, having a rectangular eye and a forwardly directed hook of a width closely approximating the width of the said eye adapted to hook onto the cross bar at the rear of the eye of an adjacent link, which consists in bending a piece of rod or wire to U-shape, bending up the ends of the arms of the U at right angles to the plane of said U, bending said arms towards each other, each through a right angle, at points closely behind the last formed bend whereby a rectangular eye is formed and the ends of the rod that project at right angles to the plane of the eye are brought to lie alongside each other, and finally bending said projecting ends forwardly to form a forwardly directed hook.

7. A sprocket chain link such as herein described formed from metal rod by bending operations without subjecting it to twisting or tortional action, when constructed according to the method stated in claim 6.

GEORGE HENRY GREEN. 

